"For many people, Sunday risks being felt and lived merely as a weekend," he said.

He added, "today to remain faithful one very often has to swim upstream."

He urged his audience to use their own holidays to restore their spirit as well as their bodies.

On Tuesday the Vatican will issue the Pope's latest Apostolic Letter, Dies Domini - The Day of the Lord - which will spell out more extensively his thoughts on this issue.

"Why not take this little volume with you and dedicate a few hours of calm reading?" he said.

No more foreign trips until October

The Vatican said the Pope skipped a recitation of the rosary on Saturday night on Vatican Radio to avoid non-essential public engagements. Correspondents said he sounded tired in his address.

He leaves on Wednesday afternoon for a two week private rest in the northern Dolomite mountains of Italy, during which he will only make four public appearances.

After his return he will stay at his summer residence in the Alban Hills south of Rome until mid-September.